Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenues (Note 1(b))	$ 0	$ 0	$ 0	$ 0
Operating costs and expenses:
Selling, general and administrative	17,230	16,391	33,182	33,007
Research and development	16,982	16,595	38,868	29,960
Total operating costs and expenses	34,212	32,986	72,050	62,967
Loss from continuing operations	(34,212)	(32,986)	(72,050)	(62,967)
Other income (expense):
Interest income (expense), net	1,495	(242)	2,556	(473)
Other income (expense), net	3,722	48,492	(7,563)	58,463
Total other income (expense)	5,217	48,250	(5,007)	57,990
(Loss) income from continuing operations before income taxes	(28,995)	15,264	(77,057)	(4,977)
Benefit (provision) for income taxes from continuing operations	212	(370)	8,454	698
(Loss) income from continuing operations	(28,783)	14,894	(68,603)	(4,279)
Income (loss) from discontinued operations, net of income taxes (Note 11)	388	(1,150)	21,053	2,205
Net (loss) income	$ (28,395)	$ 13,744	$ (47,550)	$ (2,074)
Basic (loss) income per share:
(Loss) income per common share from continuing operations ($ per share)	$ (0.26)	$ 0.15	$ (0.63)	$ (0.04)
Income (loss) per common share from discontinued operations ($ per share)	0	(0.01)	0.19	0.02
Net (loss) income per common share ($ per share)	(0.26)	0.13	(0.43)	(0.02)
Diluted (loss) income per share:
(Loss) income per common share from continuing operations ($ per share)	(0.26)	0.14	(0.63)	(0.04)
Income (loss) per common share from discontinued operations ($ per share)	0	(0.01)	0.19	0.02
Net (loss) income per common share ($ per share)	$ (0.26)	$ 0.13	$ (0.43)	$ (0.02)
Weighted average shares outstanding:
Basic (shares)	110,345,135	102,597,059	109,744,405	101,747,416
Diluted (shares)	110,345,135	112,617,150	109,744,405	101,747,416